Explosion-engine.



N0. 758,189. PATBNTBD APR. 26. 1904. LJ. MUMULLBN a. M. H. ROBINSON.

EXPLOSION ENGINE.'

APPLIQATION HLVBD Mmm, 190s.

N0 MODEL.

Patented April 2e, 1904.'

vKENRIC JAMES vIVICMULLEN AND MARK4 HEATON ROBINSON, OF RUGBY;

ENGLAND, ASSIGNORS TO WILLANS AND ROBINSON,

RUGBY, ENGLAND.

LIMITED, OF

EXPLQSIONv-E-N-iuus.l

vSPIICIFICAJ.EION forming part of Letters `Patent No. 758,189, datedApril 26, 1904.

Application filed August 2.77,

To a/ZZ whom it may concern;

. Be it known ,that we, KnNRIc JAMES Mo- MULLEN and MARK HEA'IONROBINSON, engineers, subjects of the King of Great Britain,

5 residing at Victoria W'o'rks, Rugby, England, have invented certainnew and useful Improvements in Explosion-Engines, of which thefol- Y bya portin which there Yis a valve with a res,

lowing is'a specilication. c This invention is applicable to gas `oroilengines working on the well-known four-stroke or Otto cycle, inwhich, owing to high speed of rotation, it is desired to cushion theline of working parts in such manner as to retain the brasses inconstant thrust.7 Such engines are preferably of the inverted verticalpattern, and the following description applies thereto; but they mayalso be made horizontal or in-4 clined. VThe working cylinder issingle-acting and may be open at the lower end. The piston is connectedby a piston-rod to a guidepiston working in' a guide-cylinder, thepistonrod passing through a gland in the cover of such guide-cylinder.The guide working in the said cylinder is preferably in the form of atrunk-piston, to which a connecting-rod is attached in the usual manner.The guide-cylinder forms also the air-cushioncylinder, operatingsubstantially in the samemanner as in the well-known W'illanssteam-engine. At the lower end of its stroke the guide-piston uncovers aport which is in communicationy with the atmosphere, or air may beadmitted by an automatic non-returnvalve.` The air shut in is as thepiston rises compressedin the upper end of the guide-cylinder and givesthe desired cushioning effect. On the next downstroke it expands anddoes work upon the guidepiston with very little loss. Such cushioningeiect, however, is not required -upon those upstrokes during which theair or gas and air required for the next' explosion are being compressedin the Vworking cylinder. Such compression in the working cylinder givesof itself the necessary cushioning, and if air-cushioning in theguide-cylinder is added at the same time the total holding-down effect*vupon the crank-pin will be much in excess of what is required and willsubject the mechan-` Serial No. 170,982. (No model.) v

ism to needless stresses and to increased friction. Y

In order to make beneficial use of the com pression of air in the guideor air-cushion cylinder 'during those strokes when it is not requiredfor cushioning effect, we arrange that the top Yof the said cylindershall communicate ervoir. At the lowerl end of the working cyll inderisa port which is uncovered bythe piston at the'end of its downstroke.Such port is in communication with the reservoir by a passage in whichthere is also a-valve, or the piston itselfif made sufficiently long tokeep the ports closed at all times except when it is at the bottom ofits stroke, may itself act as the valve. During the upstroke, in whichcushioningA in the guide-cylinder is required,

the valve in the port leadingi'rom the guidecylinder to the reservoir isclosed and air isv compressed in the guide-cylinder, not being able toescape into the reservoir; butfduring the intermediate strokes, whencushioning in the guide-cylinder is not required, the valve is openedand the air is allowed to pass into ythe reservoir, theproportions ofthe latter being such that the highest pressure reached is moderate,amounting to only a fewI pounds per square inch.' The reservoir willYthus be replenished during every compression'- upstrolre of the Workingpiston, and the air will be retained inthe reservoir until the end ofthe succeeding working downstroke, when, the valve between the reservoirand the port in the working cylinder being opened, the air will rushinto the working cylinder as soon as the piston uncovers the port andfor as long as it remains uncovered, AThis air will act as a scavengingcharge', blowing the products of combustion out through theexhaust-valve and more or less insuring that the clearancespace shall befilled with pure air at the end of the succeeding up or exhauststrok'e.vDuring the next downstroke, when air or air and gas are being drawn intothe workingcylinder for subsequent compression, the valve between thereservoir and the port in the working cylinder may be kept closed, sothat when the port is uncovered by the piston no air shall enter thecylinder. During this downstroke air enters the guide or air-cushioncylinder by an automatic valve, which is kept closed by the pressure ofthe air in that cylinder at all other times, except when the pistons areat or near their lowest position, when there is naturally no pressure inthe air-cushion cylinder.

Alternatively the disposition of valves may be such that a portiononly'of the contents of the reservoir shall be driven into the workingcylinder as a scavenging charge and some shall be retained in thereservoir to be sent into the cylinder at the completion of the chargingdownstroke, with the effect of adding to the weight of the explosivemixture in the cylinder at that time.

In the accompanying drawings, Figure l shows a vertical section of asingle-cylinder engine constructed according to this invention. Fig.l 2shows a vertical section of a portion of such engine embodying amodification.

A is the working cylinder, in'which the single-acting piston Breciprocates. The Working piston B isv connected by the piston-rod C Cto a guide-piston D, working in aY guidecylinder E, the connecting-rod Fbeing attached to the'guide-piston inthe usual manner. At the lower endof its Stroke the guidepiston D uncovers a port or ports G G, which arein communication with the atmosphere, or the ports G may be replacedA byan automatic non-return valve P, as shown in Fig. 2.' The air shut in asthepiston D rises is compressed in the upper end ofthe guide-cylinder Eand gives the desired cushioning effect. the next downstroke orsuction-stroke it expands'and does work upon the guide-piston D,

land thus prevents any reversal of the direction of strain on theconnecting-rod, which is always kept in compression. e In order to makebeneficial use of the compression o-f air in the guide or air-cushioncylinder E during the compression-strokewhen it is notrequired forcushioning effect, we arrange that the top of the said cylinder E shallcommunicate by a port H, in which there is a valve J, with a reservoir KK K.

At the lower end of the working cylinder A is a port or ring of ports LL L, which are uncovered by the piston B at the end of its downwardstroke. Such ports are in communication with the reservoir K.

VDuring the upstroke, in which cushioning in the guide-cylinder E isrequired, the valve J is closed and air is compressed in theguidecylinder E; but during the intermediate strokes, when cushioning inthe guide-cylinder E is not required, the valve J is opened and theairis allowed to pass into the reservoir K K K, the proportions of thelatter being such that the highest pressure reached is moderate,amounting only to a few pounds per square inch. rlhe reservoir K K Kwill thus be replenished during every compre-ssion-upstroke of theworking piston B and the air will be retained in the reservoir K K Kuntil the end of the succeeding working downstroke, when the port orports L L L between the reservoir K K K and the working vcylinder Abeing opened the air willl being drawn into the working cylinder Athrough the admission-valve N for subsequent compression,communicationis established between the reservoir and the cylinder at the bottom ofthe intake-stroke. If there is any pressure left in the reservoir, allthat happens is that there is a slight addition to the air in workingcylinder A. During the downward stroke air enters the guide o raircushion cylinder' E by the ports G or automatic valve P.

R indicates a shaft carrying cams r r' r2 for operating the valves N, M,and J respectively.

What we claim isl. In a four-stroke cycle explosion-engine thecombination with the working cylinder and piston of an air-cylinder andpiston connections between the two pistons such that they move together,an air-reservoir, means for admitting air to the air-cylinder beforeeach instroke of the working piston, a valve admitting air to thereservoir from the air-cylinder during the compression-stroke of theworking piston and preventing the escape of air from the air-cylinderduring the exhauststroke, and means for admitting air from the reservoirinto the Working cylinder during the exhaust-stroke of the workingpiston.

2. In a four-stroke cycle explosion-engine the combination with theworking cylinder and piston of an air-cylinde-r in line with theordinary cylinder a piston in the air-cylinder a piston-rod connectingthe two pistons, an airreservoir, means for admitting air to theairvcylinder before each instroke of the working piston, a valveadmitting air to the reservoir from the air-cylinder during thecompressionstroke of the vWorking piston and preventing the escape ofair from the air-cylinder during the exhaust-stroke of thev workingpiston and means for admitting air from the reservoir into the workingcylinder during the exhauststroke of the working piston.

3. In a four-stroke cycle explosion-engine the combination with theworking cylinder and piston ofan air-cylinder and piston connectionsbetween the two pistons such that they move together, an air-reservoir,means for ad- IOO IIO

dinary cylinder, a piston in the air-cylinder,

a piston-Tod connecting the two pistons, an air-reservoir, means foradmitting au' to the air-cylinder before each instroke of the Workingpiston, a valve admitting air to the reservoir from the air-cylinderdring the cornpressiOn-stroke of the Working piston and preventing theescape of air from the air-cylinder during the exhaust-stroke of theWorking piston and a port in the outer end of the Wokiug cylinder incommunication with the reservoir.

KENPJO JAMES MGMULLEN. MARK HEATON ROBINSON.

Writnesses:

J OHN HENDERSON WHITEHEAD, L Y FREDK. C.VVEATHERLY.

